dipirro@amber.DEC (Are we having fun yet?) (10/24/85)
I recently watched a program on PBS called "What Einstein Never Knew." It was primarily a discussion of recent developments in the area of Unified Field Theory. Physicists appear to be following several different paths. Experimental physicists are still trying to find relationships between the four forces in the context of the universe as we know it (and have recently found a connection between electromagnetic and weak nuclear forces). Theoretical physicists are proposing new universe concepts which cannot be verified through experimentation directly. One such theory is called "supersymmetry." It talks of all things being symmetrical in a universe which has 10 or 11 physical dimensions, in which we see only three. Another theory was called the "string" theory (I think) and can explain the relationship between all four major forces. I'd be interested to know if any of the new theories will cause reconsideration of some of Einstein's theories of relativity. I'm particularly interested in the speed of light being a limiting factor for space travel. Most people agree that as long as speed-of-light restrictions apply, it is impractical for intelligent life forms to travel to different star systems (unless, of course, their solar system is about to blow up). Before he died, Einstein was thinking about the curvature of space due to gravity. He believed that space is warped by objects with mass. Even light could not travel "directly" from point A to point B but had to follow the curvature of space. That implied that if one could travel directly from point A to point B that one could get there faster than light. However, one need not travel faster than light-speed. This is an oversimplified view (but I can't help that...Its how my mind works). It seems to me that any Unified Field Theory could help explain if and how its possible to travel "faster than light," since it must involve the relationship between gravity and electromagnetic forces. Could anyone out there enlighten me? I think that space travel (particularly faster-than- light space travel) belong here in net.space. If people disagree, we can move the discussion elsewhere. Steve DiPirro Digital Equipment Corp. "If space itself is warped, then so must I be..."
henry@utzoo.UUCP (Henry Spencer) (10/27/85)
> I'd be interested to know if any of the new theories will cause > reconsideration of some of Einstein's theories of relativity. I'm particularly > interested in the speed of light being a limiting factor for space travel. Reconsideration of the General Theory of Relativity is virtually certain, partly because it appears to be incompatible with quantum mechanics and partly because it contains major internal anomalies like the possibility of the Tipler time machine. [Briefly, intense rapidly-spinning gravity fields can be used to build a time machine with unlimited range into both past and future.] Alas, General Relativity is just basically the current theory of gravitation. The Special Theory of Relativity, which sets the various speed-of-light limits, is on much firmer ground and is unlikely to be invalidated by new theorizing. Of course, it is always possible that some subtle way to bypass it may be found. > Most people agree that as long as speed-of-light restrictions apply, it is > impractical for intelligent life forms to travel to different star systems > (unless, of course, their solar system is about to blow up). Fortunately, wrong. Within relativity, starships are slow and expensive, but they are neither impossible nor impractical. In recent years the literature on interstellar travel (notably the JBIS "Interstellar Studies" issues) has contained dozens of starship and starprobe concepts. For example, if you ignore a couple of decades of engineering development and the associated funding delays, we have the technology to build antimatter rockets right now. There are any number of ways to reach tens of percent of the speed of light, which suffices for interstellar flight within human lifetimes. Not for interstellar commuting, mind you; near-term interstellar trips are likely to be long enough that you could not make many in one lifetime. For that, we need either highly-relativistic travel or (preferably) faster-than-light travel. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
dipirro@louie.DEC (Are we having fun yet?) (10/30/85)
>> I'd be interested to know if any of the new theories will cause >>reconsideration of some of Einstein's theories of relativity. I'm particularly >>interested in the speed of light being a limiting factor for space travel. >>Most people agree that as long as speed-of-light restrictions apply, it is >>impractical for intelligent life forms to travel to different star systems >>(unless, of course, their solar system is about to blow up). > >Most people are wrong! Interstellar flight at sublight speeds is almost >certainly practical with forseeable technology. A few years out of one's >life is not an impossible price to pay to get to a place with room to grow. >One will not casually visit other star systems at sublight, but colonization >is quite practical. I've gotten quite a few flames of this nature. I misrepresented my own views. So I guess I deserve it. I realize that space travel at close-to-light speeds is feasible in the foreseeable future. It may even be practical for colonization or research. However, travel to any star system at nonrelativistic speeds will take a LONG TIME and require some clever mechanism to support humans for the trip duration. However, if those humans do not intend to return, then they can travel at nearly the speed of light and into the future at the same time. They are gambling that technology won't find a better way to do this in the time that slipped by. These people might find much more advanced humans already at their destination when they get there. I still contend that its not practical, economically or otherwise. That is not to say that we shouldn't or won't do it. I think we will as soon as we're able. Impracticality has never stopped humans before. Steve DiPirro Digital Equipment Corp. "All my views are also the views of my cats, Hughie & Louie."
friesen@psivax.UUCP (Stanley Friesen) (10/30/85)
In article <1024@decwrl.UUCP> dipirro@amber.DEC (Are we having fun yet?) writes: > > I'd be interested to know if any of the new theories will cause >reconsideration of some of Einstein's theories of relativity. I'm particularly >interested in the speed of light being a limiting factor for space travel. >Most people agree that as long as speed-of-light restrictions apply, it is >impractical for intelligent life forms to travel to different star systems >(unless, of course, their solar system is about to blow up). I disagree, there is a completely different way to handle the problem, "cure" old-age. If people didn't age and die they would not care how long something took. I got this idea from watching "Cacoon". -- Sarima (Stanley Friesen) UUCP: {ttidca|ihnp4|sdcrdcf|quad1|nrcvax|bellcore|logico}!psivax!friesen ARPA: ttidca!psivax!friesen@rand-unix.arpa
mazlack@ernie.BERKELEY.EDU (Lawrence J. &) (10/31/85)
>>>interested in the speed of light being a limiting factor for space travel. >>>Most people agree that as long as speed-of-light restrictions apply, it is >>>impractical for intelligent life forms to travel to different star systems >>>(unless, of course, their solar system is about to blow up). >> >>Most people are wrong! Interstellar flight at sublight speeds is almost >>certainly practical with forseeable technology. A few years out of one's >>life is not an impossible price to pay to get to a place with room to grow. >>One will not casually visit other star systems at sublight, but colonization >>is quite practical. > >I've gotten quite a few flames of this nature. I misrepresented my own views. >So I guess I deserve it. I realize that space travel at close-to-light speeds >is feasible in the foreseeable future. It may even be practical for colonization >or research. However, travel to any star system at nonrelativistic speeds will >take a LONG TIME and require some clever mechanism to support humans for the >trip duration. However, if those humans do not intend to return, then they can >travel at nearly the speed of light and into the future at the same time. They >are gambling that technology won't find a better way to do this in the time >that slipped by. These people might find much more advanced humans already at >their destination when they get there. > If someone travels at near light speed, isn't elapsed time for she/he less than the elapsed time for someone traveling at a much slower speed. If so, it wouldn't be too bad a deal for the traveller in terms of life-time spent - although the society that sent him/her would undergo considerable change. Whether or not there could be economic payoffs would depend on the time frame of the investor. For example, forest product companies plant trees that will not be harvested for 15 years while other investors think in terms of weeks or minutes for their payoffs. If I'm right on the relativistic time differentiation, can anyone tell me how to actually calculate the difference??? ...Larry Mazlack MAZLACK@ERNIE.BERKELEY.EDU